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公开(公告)号：US20180208491A1
公开(公告)日：2018-07-26
申请号：US15478456
申请日：2017-04-04
Applicant: Hitachi, Ltd.
Inventor： Yuya KIMURA , Shinichi YOSHIKAWA , Shoko MIYAMAE , Hajime IKUTA
CPC classification number: C02F3/303 , C02F3/006 , C02F3/307 , C02F2101/16 , C02F2103/20 , C02F2103/343 , C02F2103/346
Abstract: Provided is a method for treating ammoniacal nitrogen in wastewater performed via biologically oxidizing ammoniacal nitrogen, and producing nitrite nitrogen and nitrate nitrogen at a desired rate. In the method, ammoniacal nitrogen is oxidized by bacterial sludges to produce at least either of nitrite nitrogen and nitrate nitrogen. Specifically, the method includes an inactivating treatment step of treating the bacterial sludges with an inactivating operation via sterilizing bacteria or causing bacteriostasis, and a nitrifying treatment step of oxidizing the ammoniacal nitrogen by the bacterial sludges thus treated in the inactivating operation. Production amounts of the nitrite nitrogen and the nitrate nitrogen are controlled by adjusting biomass of the bacterial sludges to be treated in the inactivating operation, and/or a time interval between the inactivating operations each repeatedly performed in combination with the nitrifying treatment step.
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公开(公告)号：US20210147270A1
公开(公告)日：2021-05-20
申请号：US17046347
申请日：2019-03-05
Applicant: HITACHI, LTD.
Inventor： Makiko UDAGAWA , Shoko MIYAMAE , Yuuya KIMURA , Shinichi YOSHIKAWA
Abstract: The present invention provides a nitrogen treatment method which can suppress the production of nitrate nitrogen to stabilize the concentration of nitrite nitrogen in a nitritation treatment in which ammoniacal nitrogen is biologically oxidized to produce the nitrite nitrogen. A nitrogen treatment method includes a nitrification treatment step of producing nitrite nitrogen by oxidizing ammoniacal nitrogen contained in water to be treated, using microbial sludge, wherein: a volume load of the ammoniacal nitrogen in the nitrification treatment step is set to a high load of 0.3 kg-N/m3·day or more and 5 kg-N/m3·day or less; and in the nitrification treatment step, at least one of a treatment of adjusting a pH of the water to be treated to pH 8 or more and pH 10 or less and a treatment of applying an inactivating operation for sterilizing microorganisms or causing bacteriostasis to the microbial sludge is performed.
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公开(公告)号：US20180179092A1
公开(公告)日：2018-06-28
申请号：US15478842
申请日：2017-04-04
Applicant: Hitachi, Ltd.
Inventor： Shinichi YOSHIKAWA , Yuya KIMURA , Shoko MIYAMAE
IPC: C02F3/30
CPC classification number: C02F3/307 , C02F2101/16 , C02F2209/02 , C02F2301/10 , C02F2303/10 , Y02E50/343 , Y02W10/30
Abstract: Provided is a wastewater treatment apparatus and a wastewater treatment method, in which denitrification process by anaerobic ammonium oxidation method can be stably performed at low cost. The wastewater treatment apparatus includes an ammonium oxidation tank and a heating tank in which the microbial sludge withdrawn from the ammonium oxidation tank is subjected to heat treatment. A wastewater treatment method is to heat the microbial sludge withdrawn from the ammonium oxidation tank by using heat supplied from a digestion tank in which waste sludge is digested by anaerobic microorganisms or from a heat source for heating the waste sludge to be digested in the digestion tank, and to return the microbial sludge, in which activity of nitrite oxidizing bacteria is reduced by the heat treatment, to the ammonium oxidation tank, so that the ammonium nitrogen contained in the wastewater is oxidized to nitrite nitrogen.
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